18 F-sodium fluoride positron emission tomography of the racing Thoroughbred fetlock: Validation and comparison with other imaging modalities in nine horses.

The study presents a validation of positron emission tomography (PET) using 18 F-sodium fluoride (18 F-NaF) in identifying early signs of stress remodeling in racehorses, suggesting that it could be more efficient in detecting subtle injuries than other imaging techniques.

Study Overview and Objective

• The research focused on testing the efficiency of Positron emission tomography (PET) using 18 F-sodium fluoride (18 F-NaF) as a method for detecting early signs of stress remodeling in racehorses. The researchers sought to validate its clinical use and assess its precision in detecting bone lesions compared to other imaging modalities, clinical examination, and pathology.

Methodology

• The researchers conducted an experimental exploratory study where 20 fetlocks from nine Thoroughbred racehorses were imaged using 18 F-NaF PET, computed tomography (CT) and scintigraphy. They also used magnetic resonance imaging for five of the fetlocks and examined four histologically.
• The images produced were independently reviewed by three board-certified radiologists. The team correlated the imaging, clinical, and histopathological findings to evaluate the effectiveness of different techniques.

Results

• The study found that PET imaging is not only well-tolerated by horses but also successfully identifies focal areas of 18 F-NaF uptake in instances other imaging techniques could not detect any abnormalities.
• Particularly, PET proved more efficient than alternative methods in identifying abnormalities in the proximal sesamoid bones. The activity of these lesions could be measured using maximal standardised uptake values.
• The regions that showed 18 F-NaF uptake corresponded to areas of increased vascularity and increased osteoblastic activity, thus confirming the efficacy of PET.

Conclusion

• Despite the limited number of cases, the study concluded that 18 F-NaF PET imaging is a feasible method for detecting stress remodeling in Thoroughbred racehorses.
• The comparative analysis showed that PET compares favorably with other imaging modalities in detecting early signs of stress, presenting it as a beneficial tool in preventing potential catastrophic musculoskeletal injuries in horses.